The attack was demonstrated by Rich Smith, head of research for offensive technologies and threats at HP Systems Security Lab, at the EUSecWest security conference in London on Wednesday. Smith toldDark Reading that such as "permanent denial of service" attack could be carried out remotely over the internet.

Theoretically the attack could be both more effective (as the damage caused would be harder to recover from) and cheaper than conventional denial of service attacks, which typically rely on hackers paying to rent control of a network of compromised PCs.

The PhlashDance approach relies on exploiting frequently unpatched vulnerabilities in embedded systems, such as flaws in remote management interfaces, to get access to a system. That alone wouldn't be enough, but because firmware updates are seldom secured, the possibility exists of making an update that effectively trashes a system.

Smith is calling on vendors to authenticate the mechanism as one way of defending against such attacks. He is demonstrating a tool to search for vulnerabilities in firmware, as well as an attack mechanism to corrupt vulnerable firmware at EUSecWest.

There's no record of such an attack even occurring and other security watchers are sceptical over whether crackers could make money - the main motive for denial of service attacks - from such an approach. Both H D Moore of Metapolit fame and the Hack a Day blog reckon that exploiting vulnerabilities to plant malware in firmware is a far more insidious and dangerous type of attack than simply destroying systems.

Another presentation at EuSecWest will demonstrate a proof of concept rootkit capable of covertly monitoring and controlling Cisco routers. The Cisco IOS rootkit software was developed by Sebastian Muniz, of Core Security. ®